CMOS (Complementary Metal Oxide Semiconductor) sensors are often used in digital video cameras and so on because the CMOS sensors can be manufactured with low cost. It is general that the CMOS sensor photographs each scanning line by turns from the top part of the image to the bottom part thereof, which is called as a rolling shutter type, instead of photographing whole of a frame at the same time. Because timing when the top part of the image is photographed differs from timing when the bottom part of the image is photographed, there is a problem that moving object photographed by the CMOS sensor may be distorted. This distortion is called as a focal plane distortion.